One or more aspects of the present invention generally relate to the field of artificial intelligence and computer security, and more specifically, to a vision based test to distinguish computers from humans.
The term “CAPTCHA” is an acronym for “Completely Automated Public Turing Test to Tell Computers and Humans Apart”. A CAPTCHA could be implemented by a program that protects websites against bots by generating and grading tests that humans can pass but current computer programs cannot.
CAPTCHAs are wildly used on the internet to tell computers and humans apart. However, with technologies like pattern recognition and artificial intelligence, computers also have the capability to recognize some simple CAPTCHA. To avoid being recognized by computers, some CAPTCHA are becoming more and more complex and fuzzy. This leads to a side effect, namely, sometimes even humans find it quite difficult to recognize the CAPTCHA. Further, even though some CAPTCHA are more complex and fuzzy, some computers can still recognize them.